The present invention relates to novel chromene compounds and the use of the chromene compounds.
Photochromism is a reversible action of a compound which quickly changes its color when it is irradiated with light containing ultraviolet rays and resumes its initial color when it is no longer irradiated with light but is placed in a dark place. The compound having this property is called photochromic compound. Various compounds have so far been synthesized. Among these photochromic compounds, the chromene compounds exhibit good light resistance and develop colors of a wide variety of tones such as yellow color to blue color, and have been vigorously studied in recent years. Some of the chromene compounds that are developed have already been put into practice as photochromic materials for organic photochromic lenses.
The organic photochromic lens stands for a lens that develops color in an environment where it is irradiated with ultraviolet rays such as outdoors and can be used as sunglasses, and loses its color and returns to its colorless or slightly tinted state in an environment where it is irradiated with weak ultraviolet rays, such as indoors. The organic photochromic lens must satisfy such requirements that it develops a color quickly and densely upon the irradiation with ultraviolet rays and quickly loses color upon the interruption of ultraviolet rays, that it is not colored after faded, and that it exhibits excellent light resistance.
Some chromene compounds found so far exhibit excellent photochromic properties, such as quick color developing/fading rate and a high color density in a solution. When dispersed in a high-molecular matrix such as a plastic material, however, the chromene compound fails to exhibit its intrinsic excellent photochromic properties to a sufficient degree arousing such problems as decreased color density, decreased fading rate and decreased light resistance. These problems appear conspicuously when the chromene compound is dispersed in a rigid high-molecular matrix, deteriorating the fading rate to a conspicuous degree. No method for effectively solving the above problems has been known, and no chromene compound has, either, been known which can be dispersed in a plastic lens that must have a large strength and a hardness to exhibit photochromic properties to a sufficient degree.
For example, the specification of PCT Patent Application WO96/14596 discloses a chromene compound represented by the following formula (A), 
When dispersed in a high molecular matrix, however, the above chromene compound exhibits a low color-developing sensitivity, a low fading rate, and is colored (also called coloring upon deterioration) even in a state of not irradiated with light when it is used as, for example, a photochromic material for extended periods of time and, further, develops color of a decreased density when irradiated with light.
The specification of PCT Patent Application WO97/48762 discloses a chromene compound represented by the following formula (B), 
However, this chromene compound, too, has a problem of slow fading rate when it is dispersed in a high-molecular matrix.
Further, German Application Publication DE19902771A1 discloses a chromene compound represented by the following formula (C), 
When dispersed in a high-molecular matrix, however, the above chromene compound exhibits a fading rate which is not of a satisfactory level.
U.S. Pat. No. 6,113,814 discloses a chromene compound represented by the following formula (D), 
having a polyalkyleneoxy group with a polymerizable group bonded to one terminal thereof so as to be copolymerizable with a monomer that serves as a high-molecular matrix. This compound, however, has a problem of slow fading rate when it is copolymerized with a monomer that imparts a high hardness or is dispersed in a high-molecular matrix having a high hardness.
It is therefore an object of the present invention to provide a chromene compound which, when dispersed in a high-molecular matrix, exhibits further improved photochromic properties, a high color-developing sensitivity, a high fading rate, less color upon deterioration, and permits photochromic properties to be deteriorated little that is represented by a drop in the color density, i.e., exhibits photochromic properties maintaining excellent light resistance.
The present inventors have conducted keen study in an effort to develop a chromene compound that exhibits excellent photochromic properties in a high molecular matrix. As a result, the inventors have discovered a novel chromene compound which exhibits a high color-developing sensitivity and a high color density even when it is dispersed in a high-molecular matrix, and exhibits a high fading date, less color upon deterioration and exhibits photochromic properties maintaining excellent light resistance, and have completed the present invention.
That is, the present invention is concerned with a chromene compound represented by the following general formula (1), 
wherein a group represented by the following formula (2), 
xe2x80x83is an aromatic hydrocarbon group or an unsaturated heterocyclic group;
R1 is a hydroxyl group, an alkyl group, a trifluoromethyl group, an alkoxy group, an alkoxycarbonyl group, a carboxyl group, an alkoxymethyl group, a hydroxymethyl group, an aralkoxy group, an amino group, a substituted amino group, a cyano group, a nitro group, a halogen atom, an aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted heterocyclic group having a nitrogen atom as a hetero atom and in which the nitrogen atom and an indene ring are coupled together, or a condensed heterocyclic group in which the heterocyclic group is condensed with an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and p is an integer of 0 to 3;
R2 is a hydroxyl group, an alkyl group, a trifluoromethyl group, an alkoxy group, an alkoxycarbonyl group, a carboxyl group, an alkoxymethyl group, a hydroxymethyl group, an aralkoxy group, an amino group, a substituted amino group, a cyano group, a nitro group, a halogen atom, an aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted heterocyclic group having a nitrogen atom as a hetero atom and in which the nitrogen atom and a ring of the group represented by the above formula (2) are bonded together, or a condensed heterocyclic group in which the heterocyclic group is condensed with an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and q is an integer of 0 to 3;
R3 and R4 are, independently from each other, a group represented by the following formula (3), 
wherein R5 is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, R6 is a hydrogen atom, an alkyl group or a halogen atom, and n is an integer of 1 to 3,
a group represented by the following formula (4) 
wherein R7 is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and m is an integer of 1 to 3,
a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or an alkyl group, or R3 and R4 together may constitute an aliphatic hydrocarbon ring or an aromatic hydrocarbon ring; and
a cyclic group spiro-bonded to the first position of an indene ring represented by the following formula (5), 
xe2x80x83is an aliphatic hydrocarbon cyclic group which is an unsubstituted monocyclic ring having 7 to 20 carbon atoms in the ring, an aliphatic hydrocarbon cyclic group which is a monocyclic ring having 4 to 20 carbon atoms in the ring and has at least one substituent selected from alkyl group, alkoxy group, amino group, substituted amino group, substituted or unsubstituted aralkyl group and substituted or unsubstituted aryl group, a crosslinked cyclic spiro-cyclic aliphatic hydrocarbon cyclic group which may have at least one substituent selected from the group consisting of alkyl group, alkoxy group, amino group, substituted amino group, substituted or unsubstituted aralkyl group and substituted or unsubstituted aryl group, or a substituted or unsubstituted cyclic group having 4 to 20 carbon atoms in the ring, the cyclic group having at least any one of the following groups in a number of 1 or 2 or more (but not containing two oxy groups), 
wherein R is an alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a carboxyl group or an alkoxycarbonyl group.
The chromene compound according to the present invention has, in the molecules thereof, no polyalkyleneoxy group with a polymerizable group bonded at one terminal thereof. Therefore, when the chromene compound is mixed with, for example, a monomer to be polymerized so as to be dispersed in a high-molecular matrix of a high hardness, the molecular motion is suppressed little, and the isomerization takes place smoothly without causing the fading rate to be greatly decreased.
Among the above-mentioned chromene compounds of the present invention, a high fading rate is exhibited by the chromene compound in which a cyclic group spiro-bonded to a first position of the indene ring represented by the above formula (5) is {circle around (1)} an aliphatic hydrocarbon cyclic group which is an unsubstituted monocyclic ring having 7 to 15 carbon atoms in the ring, {circle around (2)} an aliphatic hydrocarbon cyclic group which is a monocyclic ring having 4 to 15 carbon atoms in the ring and having at least one substituent selected from alkyl group, alkoxy group, amino group, substituted amino group, substituted or unsubstituted aralkyl group and substituted or unsubstituted aryl group, and, particularly, the one having a substituent at the xcex2-position of spiro carbon, and {circle around (3)} a bicyclic group or a tricyclic group having 4 to 15 carbon atoms in the ring which may have at least one substituent selected from the group consisting of alkyl group, alkoxy group, amino group, substituted amino group, substituted or unsubstituted aralkyl group and substituted or unsubstituted aryl group, or {circle around (4)} a substituted or unsubstituted cyclic group having 4 to 15 carbon atoms in the ring, the cyclic group having one or two of at least one kind of group selected from the group consisting of xe2x80x94NHxe2x80x94 group, xe2x80x94NRxe2x80x94 group (where R is an alkyl group, a substituted or unsubstituted aryl group, substituted or unsubstituted aralkyl group, a carboxyl group or an alkoxycarbonyl group), xe2x80x94Sxe2x80x94 group, xe2x80x94Oxe2x80x94 group, xe2x80x94C(xe2x95x90O)xe2x80x94 group, xe2x80x94C(xe2x95x90O)Oxe2x80x94 group and xe2x80x94NHC(xe2x95x90O)xe2x80x94 group (but not containing two oxy groups).
Another invention is concerned with a photochromic material containing the above chromene compound of the present invention. Among the photochromic materials, those containing an ultraviolet-ray stabilizer exhibit a particularly high light resistance.
The chromene compound of the present invention or the photochromic material of the present invention exhibits excellent photochromic properties even when it is dispersed in a high-molecular matrix and, particularly, in a high-molecular matrix having a high hardness, and can, hence, be favorably used as a photochromic optical material. Therefore, the photochromic optical material containing the chromene compound of the present invention in the high-molecular matrix and, particularly, the one in which the high-molecular matrix has a Rockwell hardness of 80 to 120, is useful as an optical material such as plastic photochromic spectacle lenses that require a mechanical strength.
Such an optical material can be obtained by polymerization-curing, for example, a polymerizable monomer and a photochromic curable composition of the present invention containing a photochromic material of the present invention.
Further, the photochromic material of the present invention exhibits a high color density and a high light resistance and, hence, exhibits excellent photochromic properties even when it is dispersed in a high molecular matrix having a small thickness, such as a film. For example, a layer containing the photochromic material of the present invention is laminated on at least one surface of the lens to obtain an excellent photochromic lens.